@RogerSheriff - feel free to re-implement it. Licho chose C# because, regardless of its MS ties, it's a really easy language to work in. He got ZKLobby into workable, effective functionality in a tiny fraction of the time it took SpringLobby (the C++ implementation) to become usable.
StrangeMan - unless you're volunteering to re-implement the lobby in C++, nobody's going to be using JUCE here. Spring
has multiplatform lobbies, they're just missing some important features ZK needs (like multi-engine support) and the developers of those lobbies haven't added them.
And as for the Spring engine itself, it uses a lot of very-close-to-the-metal stuff to maintain sync that probably wouldn't play nice with any special framework like that.